diff --git a/specification/deviceupdate/resource-manager/Microsoft.DeviceUpdate/preview/2020-03-01-preview/deviceupdate.json b/specification/deviceupdate/resource-manager/Microsoft.DeviceUpdate/preview/2020-03-01-preview/deviceupdate.json
index f1ed6d85d826..b893af42fd06 100644
--- a/specification/deviceupdate/resource-manager/Microsoft.DeviceUpdate/preview/2020-03-01-preview/deviceupdate.json
+++ b/specification/deviceupdate/resource-manager/Microsoft.DeviceUpdate/preview/2020-03-01-preview/deviceupdate.json
@@ -860,7 +860,7 @@
       "type": "string",
       "description": "Account name.",
       "x-ms-parameter-location": "method",
-      "pattern": "^[A-Za-z][A-Za-z0-9]+$",
+      "pattern": "^[A-Za-z0-9]+(-[A-Za-z0-9]+)*$",
       "minLength": 3,
       "maxLength": 24
     },
@@ -871,7 +871,7 @@
       "type": "string",
       "description": "Instance name.",
       "x-ms-parameter-location": "method",
-      "pattern": "^[A-Za-z][A-Za-z0-9]+$",
+      "pattern": "^[A-Za-z0-9]+(-[A-Za-z0-9]+)*$",
       "minLength": 3,
       "maxLength": 36
     }